The Kona Bike Course: How Hard Is It, and How Hard Do Athletes Actually Ride It?

The Kona bike course is 181 km (112.6 mi), out and back on the Queen K Highway, with about 1,490 m (4,900 ft) of climbing. The athletes who race it ride at about 70% of their FTP for five to six hours. On paper it is one of the flatter full-distance courses. What makes it hard is the sun on the lava fields, the crosswinds near Hawi, and the marathon you have to run afterward.

This Saturday, October 10, the IRONMAN World Championship is back in Kailua-Kona, and for the first time since 2019 the men and women race on the same day. Roughly 2,500 athletes are registered. So this week we pulled together everything we know about the course. Who gets to the start line, how much time fitness and gear are worth on it, how hard athletes actually ride it, and how much you sweat out there.

Who actually rides Kona, and how many of them train with TrainerRoad?

At least 1 in 10 Kona starters train with TrainerRoad. We looked for athletes who synced a race-day file from the 2024 men’s race or the 2025 women’s race. Between those two races there were about 4,000 starters, and just over 10% of them had a Kona file in TrainerRoad. The real number is probably higher, because this only counts athletes who recorded the race and synced it.

They are strong. We took the Kona athletes whose FTP came from AI FTP Detection in the six months before the race. The typical man was at 3.6 W/kg. The typical TrainerRoad man is at 3.0. That puts the Kona man at the 79th percentile for power to weight. The typical Kona woman was at 3.4 W/kg against 2.6, which is the 86th percentile. Put simply, they are stronger than about 80% of the athletes on TrainerRoad.

That power shows up as speed. Across every outdoor ride in the six months before Kona, the typical Kona man averaged 18.3 mph. The typical TrainerRoad man averages 15.2. The typical Kona woman averaged 16.6 mph against 13.5. Both are faster than 88% of TrainerRoad athletes of the same gender.

Everyone on the start line earned a slot at another full-distance IRONMAN race. Ray Brenkus wrote about what his qualifying year took. Pros and age groupers race side by side, and the age groupers qualified on the same courses the pros race, while holding down a job.

How do you qualify for Kona?

There are two ways in for age groupers. Win your age group at a qualifying full-distance race, or finish close enough to the Kona Standard to get a slot from the Performance Pool. Since the 2026 season, the winner of each age group gets an automatic slot. If they decline it, it goes to second, then third, and then stops. Every other slot at the race goes into the Performance Pool. There, every finisher is ranked by age-graded time, which is your finish time multiplied by a factor for your age group and gender. The factors come from the Kona Standard, which is set by the top 20 percent of Kona finishers in each age group over the last five years. Since November 2025, men and women have separate pools. The 2027 qualifying season is already open, and the first races have handed out between 45 and 100 slots each.

How close to the Standard you need to be depends on the race, because the number of slots and the depth of the field both vary. We go through the whole system, the 2027 race calendar, the Kona Standard table, and what a qualifier’s training year looks like in TrainerRoad data in How to Qualify for Kona in 2027.

What does the Kona bike course look like?

The course runs 181 km (112.6 mi) from Kailua-Kona north along the Queen K to Hawi and back, with about 1,490 m (4,900 ft) of climbing in our GPX. There is only one real climb. The rest is false flat, sun, and wind.

Press play below to ride it. Turn on the upgrades and watch how far ahead of a stock setup you get over the full distance.

Kailua-Kona and Palani Road

The first 10 km get you out of town. From the pier you climb Palani Road, which briefly goes over 8%, then turn north onto the Queen Ka'ahumanu Highway. Everyone calls it the Queen K. Town is the most humid part of the course. On recent race mornings it was 74 to 80% humidity, against 57 to 64% out on the Queen K. With fresh legs and a crowd cheering, this is the easiest place on the course to go too hard.

The Queen K Highway

From Palani to Kawaihae, the Queen K rolls for about 60 km through the lava fields with no shade. It rises and falls in long false flats of 1 to 3%, past Waikoloa at about 50 km. You are never really climbing, but you are never resting either. The air temperature is only part of the heat out here. The sun beating on the black rock is the bigger problem, which is why our sweat model puts the highest sweat rates on this road rather than in town.

Kawaihae and the climb to Hawi

At Kawaihae, around 67 km, you turn onto Highway 270 and start the one real climb. It gains about 150 m (500 ft) over the 26 km to the Hawi turnaround at 93 km, and it is rarely steeper than 3%. So it is a long grind in the aero bars, not a climb you stand up for. The crosswinds are the problem. The trade winds here, which locals call the Mumuku, usually blow 15 to 20 mph and gust past 25 on a windy day. They are the reason rear disc wheels are banned at Kona. Keep the effort steady through the gusts, so there is constant tension through the drivetrain, and let the bike move under you when the wind shifts it. Excess tension in your arms and shoulders costs more than the gust does.

The return and the Energy Lab

On the way back you get the descent from Hawi, then the steepest pitch on the course: the short 6 to 7% climb from Kawaihae Road back up to the Queen K. After that it is 60 km of lava field in the midday sun. The Natural Energy Lab turn at about 170 km is where the marathon goes later in the day, and it is the hottest spot on the whole race course. By the time you ride past it the day is at full heat. Our model has the sweat rate peaking on this return leg, late morning, just past Kawaihae.

What is the course worth in time: aero upgrades or a year of TrainerRoad?

A year of TrainerRoad saves about 18 minutes on the Kona bike course. All four aero upgrades together save about 9 minutes. We simulated a 250 W FTP, 170 lb (77 kg) rider on a TT bike. With a stock setup, that rider finishes the bike leg in 5:51. Then we added aero socks, a TT helmet, deep wheels, and a tri suit one at a time, and compared those savings with the power riders actually gain in their first year on TrainerRoad.

The upgrades work, and they add up, so if you have the budget, buy them. Training wins by so much because on a course this long, every extra watt is working for five and a half hours, on the climb and into the wind. The Cost of Getting Faster runs the same comparison on a flat time trial, and this post shows where the 26 W comes from.

How hard do athletes actually ride an IRONMAN bike leg, and is Kona different?

Athletes ride a full-distance bike leg at about 70% of their FTP, and Kona is no different. The number we use for this is intensity factor, which is your normalized power for the ride divided by your FTP. An intensity factor of 0.70 means the ride was about as hard as holding 70% of your FTP the whole way. In a filtered sample of 50+ TrainerRoad athletes at the 2024 men's race, the median intensity factor was 0.695. Across 650+ athletes at the other big full-distance races it was 0.696. Same number.

What changes the number is how hilly the course is. Texas, one of the flattest courses, was ridden at 0.66. Wales, the hilliest in our sample, was ridden at 0.75. Hilly courses push normalized power up because you work hard on the climbs and coast on the descents. Kona is one of the steadiest bike legs in the sample. Normalized power there was only about 8% above average power, compared with about 10% at the other races.

Men and women ride at the same intensity. Across every race, the median was 0.695 for men and 0.700 for women. Men produce more power and go faster, but both ride the same percentage of their FTP. We did not have enough Kona women in the sample to quote an intensity number for them on their own, so we left it out.

Kona is fast. The typical Kona man averaged 20.7 mph (33.4 km/h) and got off the bike in about 5:33. At the other races it was 19.0 mph and 5:53. Kona women averaged 18.0 mph. The slow courses are the hilly ones. Wales was 16.3 mph, Leeds 16.7, and Lake Placid 17.5.

Why only 70%? Because there is a marathon afterward. Riding harder gains you a few minutes on the bike and can cost you far more on the run. That is why Norman Banick rode his top-100 Kona well within himself. The skill is holding that steady, fairly high percentage of your threshold for five to six hours while staying well inside yourself. Long rides help you get ready for a day like that, which is why TrainerRoad has Dynamic Endurance. And it is better to work out your pacing number before race day than to discover it on the climb to Hawi.

How hot is it, and how much do you sweat on the Queen K?

Expect to sweat about a liter an hour, which is 5.5 to 6 liters over the bike leg for the rider in our simulation. We built a heat-balance model for the same 250 W, 170 lb (77 kg) rider, using hourly weather from six recent race days at four points along the course. On a stock setup, that rider loses 5.45 L at an average of 0.93 L/h. After a year of TrainerRoad, the same rider loses 6.07 L at 1.09 L/h. More power makes more heat, and that outweighs the shorter time in the sun.

The sun matters more than the air temperature. Across the six race days, the temperature only ranged from 27.5 to 28.4 C (82 to 83 F). That does not sound bad, and anyone who has ridden the Queen K knows it feels far hotter than that. The lava fields and the road soak up the sun all day and radiate it back at you, and there is no shade anywhere. The thermometer does not measure that. Our model counts the direct sun, but it treats the ground as the same temperature as the air, so on the Queen K it probably understates the heat. Even so, the same rider's sweat loss ranged from 4.7 to 6.0 L across those six days. The difference between the low end and the high end was how much cloud cover there was. The Queen K and the road to Hawi have no shade, so the sweat rate is highest there. The hottest hour of the ride averages a bit over a liter, late morning on the way back past Kawaihae, and the short climb back up from Kawaihae Road around midday pushes it past 1.5 liters an hour. Humidity is a town problem. It is 74 to 80% at the start and finish, and 57 to 64% on the Queen K. In humid air, sweat does not evaporate as well, so it drips off you instead of cooling you. But at 30 km/h the airflow keeps our model rider well short of that point, except on a couple of slow pitches around midday.

This is a physics model, not a sweat test, and it could be off by about 20% either way. Your own number could be very different. In a study of 500+ athletes, sweat rates averaged 1.21 L/h and ranged from 0.26 to 5.73 L/h (Baker, 2016). To find yours, weigh yourself before and after a long hot ride. Then arrive early enough to get used to the heat, or do some heat training before you fly.

What should you eat and drink on the Kona bike?

This is general guidance from published research, not TrainerRoad data. For a race this long, aim for at least 90 g of carbohydrate an hour from a mix of glucose and fructose. Glucose on its own tops out at around 60 g/h, and fructose uses a separate pathway, which is how a mix gets you past that (Jeukendrup, 2014). Newer field studies have had trained runners taking in 120 g/h of a glucose and fructose mix through a mountain marathon with less muscle damage and no stomach trouble (Viribay, 2020), so the old ceiling is being pushed up. Practice eating that much on your long rides first, so your stomach is ready.

Sodium is harder to pin down, because people differ a lot. In a study of 500+ athletes the average was about 36 mmol per liter of sweat, roughly 825 mg (Baker, 2016). But the range ran from under 20 to over 70 mmol, which is about 400 mg to 1,600 mg per liter. You cannot assume you are average. A sweat test tells you where you sit. And the goal is not to put back every milligram you lose. Current thinking is that you are trying to keep the balance of fluid and sodium in your body steady. If you take in all the sodium you sweat out, you can overshoot, and your body responds by pulling in water to dilute it, which can leave you sweating more and losing more fluid. Salty sweaters need more sodium than most people, but for most athletes the answer is a moderate, steady intake, not a full replacement.

For fluid, have a drinking plan for anything over 90 minutes in the heat. Do not drink more than you sweat, and never so much that you gain weight (ACSM; Kenefick, 2018). Our cycling nutrition guide covers the rest.

To everyone on the start line Saturday

Most of the people racing are not pros. They qualified at a race somewhere else, trained through a winter of early alarms, and flew to an island to ride into the wind at Hawi with a marathon still to come. About 1 in 10 of them did that training with TrainerRoad, and we are proud of every one of them. If you are racing, keep the effort steady, stick to your drinking plan, and save something for the run. If you are watching, cheer loudest for the age groupers. They have the longest day out there. Matt Russell can tell you what the front of the race feels like.

Train for your own start line

You do not need a Kona slot to want a faster bike split. On a course like this, power is what makes you faster. In our simulation, a year of TrainerRoad saved nearly twice as much time as every aero upgrade combined, for a fraction of the price. Tell TrainerRoad which race you are doing and how many hours you have. It picks every workout for you and adjusts as you get faster.

Frequently Asked Questions

How hard is the Kona bike course?

The Kona bike course is 181 km (112.6 mi) with about 1,490 m (4,900 ft) of climbing, which makes it one of the flatter full-distance courses on paper. What makes it hard is the sun on the lava fields, the crosswinds on the climb to Hawi, and the marathon afterward. In a filtered sample of TrainerRoad athletes, the typical man rode it at about 70% of his FTP for five and a half hours.

How much elevation gain is on the Kona bike course?

Our GPX of the Kona bike course has about 1,490 m (4,900 ft) of climbing. Published figures range from roughly 4,200 to 5,800 ft depending on how the course is measured. The only sustained climb is the 26 km from Kawaihae to the Hawi turnaround, which gains roughly 150 m (500 ft) and rarely exceeds 3%.

How long does the Kona bike course take?

In a filtered sample of TrainerRoad athletes, the typical man at the 2024 Kona race finished the bike leg in about 5:33 at 20.7 mph (33.4 km/h), and the typical woman at the 2025 race averaged 18.0 mph. For comparison, our simulation of a 250 W FTP, 170 lb (77 kg) rider on a stock TT bike finishes in 5:51. Hilly courses like Wales and Lake Placid ran noticeably slower in the same sample.

What percentage of FTP should you ride in an IRONMAN?

Athletes in a filtered sample of TrainerRoad race-day files rode full-distance bike legs at a median intensity factor of about 0.70, which means a normalized power around 70% of FTP for the whole leg. Flat courses came in nearer 0.66 and hilly courses nearer 0.75. The right number for you depends on how well you run off the bike, so test it on long rides before race day, not on the Queen K.

Is Kona ridden harder than other IRONMAN races?

No. In a filtered sample of TrainerRoad athletes, the median intensity factor at the 2024 Kona men's race was 0.695, almost identical to the 0.696 across the other big full-distance races. Kona is faster, at 20.7 mph for the typical man against 19.0 mph elsewhere, but that is because the course is flat and the athletes are strong, not because they ride harder relative to their FTP.

How hot is Kona on race day?

Across six recent race days, daytime air temperature at the four points we modeled along the course ranged from 27.5 to 28.4 C (82 to 83 F). Humidity was 74 to 80% in Kailua-Kona and 57 to 64% out on the Queen K. Those numbers understate how it feels. The sun, the black lava fields, and the asphalt radiate heat back at you with no shade anywhere, and a thermometer does not capture that. In our sweat model, the amount of cloud cover changed sweat loss more than the air temperature did.

How many carbs per hour for an IRONMAN bike leg?

Published research supports at least 90 g of carbohydrate an hour for events this long, using a mix of glucose and fructose. Glucose alone tops out at around 60 g/h, and fructose uses a separate pathway (Jeukendrup, 2014). Newer field studies have had trained runners take in 120 g/h of a mix with no stomach problems (Viribay, 2020). Practice eating that much on long training rides before you rely on it in a race. This is general nutrition guidance, not TrainerRoad data.

Why are disc wheels not allowed at Kona?

Rear disc wheels are banned at the IRONMAN World Championship in Kona because of the crosswinds on the Queen K and the climb to Hawi, where trade winds commonly blow 15 to 20 mph with stronger gusts. A solid rear wheel acts like a sail in a crosswind. Deep-section spoked wheels are allowed, and there is no rim depth limit.